Spraying machine



June 11, 1940. T. F. BRACKETT SPRAYING MACHINE Filed April 11, 1938vllllllllIIIIIIIIIIIIIIIIIIIII szw (Ittorneg Patented June 11, 1940UNiTED STATES PATENT OFFICE SPRAYING MACHINE Tracy F. Brackett, Detroit,Micln, minor to General Motors Corporation, Detroit, Micln, acorporation of Delaware Application April 11, 1938, Serial No. 201,233

9 Claims. (01. 91-45) carriage moves. forward it is simultaneouslyshifted in proper relation to the spray equipment in compensationfor'the curvature of the body surface in the direction of conveyortravel.

Additional objects and advantages will become apparent during the courseof the followingspecification having reference to the accompanyingdrawing wherein Figured isa side elevation showing a bodysupportingcarrla'ge about to en:- gage with the elevating mechanism;Figure 2 is a perspective view illustrating the mounting of one of thecamming plates and Figure 3 is an end view showing one of the carriageabutments or cam followers in engagement with the stationary riage istoward the left in Figure 1, the move ment being imparted through a towbar 4 at the front end for connection with the continuously movingconveyor chain shown at t. This is the usual arrangement fortransporting automobile bodies such as seen at it, through the paintshop for work at succeeding stations. At each of the several roofpainting stations there may be located a reciprocating spray gun lmounted on a transverse track it substantially as disclosed in PatentNo. 2,0t3,6t3.

According to conventional automobile body design, the roof panel iscurved both longitudinally and transversely with the longitudinalcurvature being most pronounced toward the rear of the body. The rearwall of the body can be sprayed by hand but in order to reduce theamount of hand spraying necessary and to carry machine spraying to agreater extent around the curvature than is ordinarily possible it ishere proposed to compensate for the recession of the body surface byraising the work during conveyor travel so that the distance between thesurface and the gun is maintained constant throughout the engagement bya cam follower.

operation for uniform coating. Such raising of the body as the rearportion comes into the spraying zone is preferably at one end only and,therefore, the carriage is tilted forward to avoid too wide a departureof the paint receiving sur- I face from a .plane which is substantiallynormal to the direction of spray discharge.

The shifting of the carriage may be accomplished by providing suitablycontoured cam elements on either the carriage or the floor for m Foreconomy it is preferable that cam followers be mounted on the severalcarriages for engagement with camrning devices on the floor adjacent thepath of carriage travel. The cam follower may consist simply of achanneled bar 9 or the like fastened to the carriage 3 and projectedbeyond opposite sides. thereof. At each side of the carriage is locateda cam plate III up which the followers ride during conveyor travel'forshifting the curved roof surface toward the gun I.

From the forward edge of the roof panel to the high point near themiddle the surface is substantially flat and consequently no provisionneed be made for shifting the body; From the high. pointin the roofrearwardly the curvature recedes first to a smallamount and then at ahigher rate to substantially the position of the window opening in theback panel. In conformity to this curvature the cam plate is given acontour such that the follower 9 rides up a gradual slope and finally amore pronounced slope to the high point of the cam corresponding to thepoint at which spraying is cut on. From this intermediate high point onthe cam the follower rides down the opposite end of the cam until therearwheels of the carriage are again in engagement with the conveyortrack.

To keep down resistance it is proposed to provide either the can!follower or the cam with suitable anti-friction devices and in theembodiment illustrated the anti-friction devices are embodied in anendless roller chain it surrounding the cam plate it for movementthereon upon engagement by the follower 9. The chain it is of aconventional type and may consist of a series of spaced rollerssuccessively connected by a group of links.

Inasmuch as. some bodies may not require elevation during roof sprayingthe cam plate it is pivotally mounted on the floor so that it can beswung down out of the path of the cam followers 8. The hinged mounting,as shown in the drawing, includes a series of spaced plates i2 boltedtothe cam plate l0 and pivoted or pinned plates I2 is a positioning barll which engages the floor as, seen in Figure 3 for holding the camplate erect and for relieving the hinge pins from some of the strain. Adiagonal brace rod i5 is hinged at its upper end to the plate \IB boltedto the cam" and at its lower end is secured by a removable pin I! to afloor plate l8. By removing the pin H the brace l5 can slide on thefloor as the cam plate I0 is swung down.

I claim: v

1. Ina surface treating system of the character described, a travelingconveyor for work whose surface to be treated slopes in the direction ofconveyor travel, a surface treating appliance positioned in givenrelation to one portion of the slope and means to maintain asubstantially uniform relation between the appliance and the worksurface throughout the length of the slope including work shiftingmechanism constructed and arranged to shift the work in relation to theappliance in compensation for said slope. i

2. In a surface treating system, a traveling carriage for work whosesurface to be treated is curved in the direction of carriage travel, asurface treating device positioned adjacent the path of carriage travel,a ramp having a contour substantially corresponding with said surfacecurvature and means onthe carriage to ride up said ramp as an incidentto carriage travel for shifting the carriage in relation to said surfacetreating device.

3. In roof p nting apparatus of the character described, an overheadspray gun, a traveling continuous travel to the conveyor carriage so asto pass the body roof under said applicator, a v

pair of roof-contoured ramps on' opposite sides of conveyor carriagetravel, and ramp riding means carried by the conveyor to raise one endof the conveyor carriage during its travel and maintain substantiallyuniform distance between the applicator and traveling roof.

5. For insuring proper spraying distance in v 2,208,940 to floor platesl3. Also bolted to the hinged I the spray painting of a curved body roofduring body travel on a conveyor system, a traveling body carriage, adownwardly directed spray gun positioned above the line of carriagetravel, a pair of ramps on opposite sides of the path of cariage travelthrough the spraying zone and a pair of ramp engaging followers on saidcarriage for elevation of the carriage relative to the gun during itstravel.

6. In the spray painting of a curved body roof, a body conveyor systemincluding conveyor track supporting structure, a roof spraying gunhaving its nozzle directed transversely to the path of conveyor travel,a traveling conveyor carriage and cooperating camming abutments on thecarriage and supporting structure, respectively, so constructed andarranged as to ride one on the other incident to carriage travel throughthe spray zone for shifting carriage position in relation to the spraygun nozzle in compensation for roof curvature to maintain substantiallyuniform spraying distance between the curved roof surface and gun nomle.

'7. The structure of claim 6 together with antifriction loadtransmitting bearings carried by at least one of. said camming abutmentsfor engagement with the other camming abutment.

8. In a surface finishing system of the character described, a travelingconveyor system, a spray gun adjacent thereto, a carriage engageablewith the conveyor system to carry work into the spray zone of the gunand having a cam follower, a stationary camming member having ananti-friction chain tracking thereon and being positioned in relation tothe gun for engagement by the follower to direct the traveling carrlagein a path predetermined in relation to the surface curvature of thework, said path of travel .resulting in substantially uniform spacingbetween the gun and the work surface being acted the work'into the sprayzone of said gun, of

mechanism to elevate the carriage during its travel through the sprayingzone including a stationary cam having a raceway of preselected contour,a series of rollers engageable with said raceway, an endless successionof links connecting successive rollers and a cam follower'mounted on thecarriage for engagement with the chain assembly of rollers and links.

TRACY r. BaAcKn'rr.

